MathDB

1/m + 1/n - 1/(mn) = 2/5

Source: 1991 Swedish Mathematical Competition p1

April 2, 2021

Diophantine equationdiophantinenumber theory

Problem Statement

Find all positive integers

m, n

such that

\frac{1}{m} + \frac{1}{n} - \frac{1}{mn} =\frac{2}{5}